N.A.'s summary is very useful, although it implies immediate bankruptcy.
Many of the expenses are spread out over time, during which a new owner can decide with leisure whether he needs a $2000 chart plotter (Mine was $700), radar, and so on. Sails vary greatly in price and cheap ones work. No doubt there are cases in which the for-sale boat must be moved instantly, but that's not usually the case with a broker or even a private owner. Something can be worked out.
There's something else that I find important in buying a boat. Great mental anguish is expended on the "fair" price, which is always a negotiation, and during which sailboat buyers are consumed with the fear of being cheated, or of paying too much, or of making some gross mistake that will haunt them forever.
Nah. If you want the boat, pay the seller what he asks minus the percentage he expects. A 50K boat, you offer 45K, he counters at $47,500. Buy it.
Making a big deal of a few thousand makes no sense to me. It's peanuts down the ownership road, and great concern may mean you can't really afford the unpredicted outlays ahead.